This invention relates to sewing machines and, more particularly, to an arrangement for incorporation in an electronically controlled sewing machine to prevent improper sewing when a buttonhole pattern is selected and the buttonhole paddle switch and buttonhole presser foot are not properly located.
The application of electronics technology to sewing machines has resulted in a simplification in the machine-operator interface. For example, the sewing of a buttonhole pattern has been greatly simplified. The sewing of a buttonhole pattern is fully disclosed in U.S. Pat. No. 4,159,688, which issued on July 3, 1979, to Stephen A. Garron and Charles R. Odermann, the disclosure of which is hereby incorporated by reference. Simplification of the sewing of a buttonhole pattern is achieved by the electronic control of the sewing machine responding to signals generated by a buttonhole paddle switch cooperating with a buttonhole presser foot which includes a button size gauging arrangement. However, in order for the proper sewing of a buttonhole pattern, the paddle switch must be properly positioned by the operator at the start of sewing, the paddle switch being selectively movable between a retracted non-operative position and an extended operative position. If the paddle switch is not in its extended position and if the buttonhole presser foot is not moved to an initial starting position, the appropriate signals will not be generated by the paddle switch and the bottonhole will be improperly formed.
It is therefore an object of the present invention to provide an arrangement which alerts the operator that the paddle switch and presser foot are not properly positioned at the start of sewing of a buttonhole pattern.
Unfortunately, there may be times where the operator initiates the sewing of a buttonhole pattern and ignores the alarm signal for a number of stitches. The operator would then have to remove the work fabric from the sewing machine and carefully remove the stitches.
It is therefore another object of this invention to provide an arrangement which prevents stitches from being formed after selection of a buttonhole pattern unless the buttonhole paddle switch and the buttonhole presser foot are properly positioned.